newenvironment

[arnost]

mne tohle:

\documentclass{article}
\newcounter{buf}
\newcounter{pr}
\def\ex{
\setcounter{buf}{\arabic{equation}}
\setcounter{equation}{0}
\makeatletter
\def\theequation{Ex.\arabic{pr}.\arabic{equation}}
\makeatother
}
\def\endex
{
\setcounter{equation}{\arabic{buf}}
%\end{pr} < kde to ma begin?
}
\begin{document}

\begin{ex}
\begin{equation}
a=b
\end{equation}
\end{ex}
\end{document}

vytiskne

a=b                                (Ex.0.1)

arnost